Questions tagged [hvac]

(Heating, Ventilating, and Air Conditioning) For questions about installing, repairing, and troubleshooting HVAC systems.

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Office Drop Ceiling Vent HVAC Sounds so loud. Any solutions?

My office has an HVAC system with a blower room from which it is calibrated. And the air comes in through ceiling vents. Issue is that it's so loud, in my room more than others, so that I really am ...
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2 votes
1 answer
38 views

Advice on how to wire a 4 wire RGWY wifi thermostat to an old hvac with no c wire?

I have a 4 wire RGWY coming out of the wall to my old thermostat with no additional wire available for c wire. I was going to use the green one instead as I saw a tutorial online, but when I got to ...
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0 votes
1 answer
38 views

Run air handler fan without outside condenser coming on (continuous fan)

I have a traditional gas furnace and A/C system (York unit outside). The thermostat is the Honeywell T9 wifi-enabled. In the summer I want to be able to turn system to "off", turn fan to &...
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0 votes
2 answers
55 views

Compressor is intermittently turning off

I have a 16 SEER Carrier and when it works it's fabulous. Probably 8 years old. But some days it will just suddenly turn off. The Nest Thermostat keeps going, thinking it's asking for cooling, and the ...
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5 votes
2 answers
841 views

Elevating portable air conditioner's condensate drain

I'm familiar with window and split air conditioners but new to portable ones. My portable AC has an upper and a lower plugs that can be used to drain the condensation water. Both are two low for ...
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  • 151
2 votes
3 answers
40 views

Where do I connect my common wire (C wire) for smart thermostat?

I've been running 2 Nest thermostats (1 upstairs, 1 downstairs) for years that didn't require a common wire. I'm replacing them now with Ecobee3 Lite thermostats. Both thermostats control heat from ...
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0 votes
2 answers
80 views

Wiring a 120 V device to a HVAC thermostat

I'm looking control a 120 V device with an HVAC thermostat. The device is a scrubber that cleans air and should\must only run when the HVAC is running (running in the cool state, heat state, or just ...
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  • 101
0 votes
1 answer
58 views

Low refrigerant pressure on AC - tech recommends replacing evaporator coil?

So this is a follow-up to my previous AC tech horror story: Rust on outdoor ac fan motor? Tech recommends replacement? . I got a new AC tech from a small two-tech company with glowing reviews, hoping ...
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1 vote
2 answers
47 views

How can I tell if my current thermostat wiring has a C wire?

We just moved into a new house and I want to replace the thermostat. I am trying to figure out if my current setup has a C Wire. If it doesn't, then I'll need to get a new wire run -- which I want to ...
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0 votes
1 answer
42 views

can I replace two run capacitors with one dual run capacitor?

In this unit https://ameristarhvac.com/wp-content/uploads/pdf/M4AC3-Air-Conditioner-Installation-Manual.pdf Can I replace the 35uF capacitor and the 6uF capacitor with a 35/5 dual capacitor? If so, ...
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3 votes
2 answers
86 views

How to seal refrigerant lines as they enter a house

I'm reinstalling the pipe insulation that runs from my central air conditioner condenser and I noticed there is no sealant as it enters the house. I'm thinking foam wouldn't be great because the ...
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1 vote
2 answers
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Where to connect the C Wire? See pictures and diagram [duplicate]

I have Rheem RBHC-14A00NFA AC unit. I am trying to install nest thermostat but don’t know where to connect the C wire. I am attaching the picture of the wires and the diagram. Please help! Thanks
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0 votes
0 answers
31 views

Solved...AC and blower fan running when thermostat switch to on not auto

I have replaced the fan control with transformer and also the relay...and the AC well turn on along with the lower not putting it in auto just turns on which is trying to circulate the air with the ...
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1 vote
0 answers
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+100

How are these 2 Water Source Heat Pump units wired to a single Thermostat?

This is a brand new construction, 13 floor apartment building in Manhattan. I am trying to replace the stock thermostats with the new Ecobee. 3 rooms were easy but the larger living area has 2 of ...
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1 vote
1 answer
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Rust in condensate drip pan

I have a 5 year old high Efficiency Carrier HVAC system. Been having some moisture/condensation issues and was snooping around and noticed quite a bit of buildup of rust in my AC condensate drip pan. ...
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1 answer
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How do I properly wire new Honeywell thermostat?

I’m writing because I’m trying to replace my old Honeywell Thermostat with a new one. The old labels for the wires does not match what they are asking for with the new one. I’ve attached a pic of the ...
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0 votes
1 answer
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Wiring of a Vine TJ225 thermostat

How do i wire a TJ225 Vine thermostat? I have 2 red wires, a green, a white, and a blue wire. Red wires go to RH, and R, G goes to green, white to white, and the blue goes to Y on the old thermostat, ...
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0 answers
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Sewer smell in basement bathroom ONLY when central a/c is on

whenever I turned on AC , I smell like sewer in Basement bathroom only. the rest of the basement and the house is all good. this happens only in Summer when AC is on- i checked the drain on Sink,...
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1 vote
3 answers
64 views

Air conditioner upstairs

My downstairs ac unit stopped working. My upstairs unit is still running. Will my upstairs unit work harder? Upstairs is smaller unit. Downstairs is the main unit
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0 votes
1 answer
22 views

Ecobee3 lite no output for the O/B pin

The compressor runs but no cooling (Goodman reverse cycle) The old thermostat worked so I am sure the O/B lead is good. Any way to determine if the Ecobee is at fault or unthinkable operator error! ...
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0 votes
0 answers
35 views

omit a cooling stage to better align with unbalanced Heat Pump demands?

My 2002 house near Albany, NY has central heat but no AC. I've run several manual J calcs and yield 29k cooling and 53k heating. I'd like to use the heat pump for my primary heat and leave my ...
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0 votes
1 answer
25 views

Long refrigerator line in split AC

I'm considering a split AC/heat pump install for my house. However, one set of location (compressor on the ground, air outlet on second floor) would require running the refrigerant 15 vertical feet up,...
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  • 281
2 votes
3 answers
128 views

minisplit for moutain house

We bought a mountain house that has only electric-resistance heat (mostly baseboards, plus a couple of in-wall units with blowers). To reduce electricity consumption, I want install a ductless ...
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0 votes
3 answers
80 views

Does a heat pump have separate unit for heating?

I’m trying to upgrade my current HVAC system. It is a huge unit that looks like this: I went to the crawl space and I saw some flexible ducts that go to a duct that goes inside the house. So I assume ...
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1 vote
1 answer
99 views

Adding a c-wire to a Goodman A30-10C for smart thermostat

Looking for a little help installing a c-wire on my Goodman A30-10C so I can run a new Sensi smart thermostat. I currently don’t have a c-wire running to the thermostat, and don’t really know where to ...
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0 votes
0 answers
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Why does the high pressure (small) line make loud noise when new A/C is running?

Had a new 5 Ton AC installed (compressor and coil matched system) and now when the system runs there is a loud noise in the small high pressure copper line when the system is running. Cooling seems ...
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1 vote
1 answer
48 views

Help with installing Google Nest thermostat

I have a Google Nest I want to install and I saw there was an unhooked blue wire at both ends, so no big deal right? Wrong, apparently. What the heck? We have a Climatrol 170-1-080-02-00 furnace and a ...
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0 votes
2 answers
42 views

A/C not turning on when it should

Our A/C is set at 74 it is 75 in here and for 20 minutes I waited for it to kick on. It never did. I turned down to 73 and it kicked right on. Last year A/C guys said there was a delay set so they ...
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6 votes
4 answers
842 views

Do I need to vent my sealed attic?

Edit: Updated with responses The house in question is a 2-story w/ basement, with a two-zone (ground floor, and upstairs) HVAC system in NY. There is an attic with a ladder(*) housing the upstairs ...
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  • 101
1 vote
1 answer
75 views

Would a 1 lb refrigerant loss result in icing?

Just had a new unit installed in my home about three weeks ago. When I got home yesterday it wasn’t cooling properly but everything was running. HVAC technician came out and said he found a block of ...
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0 votes
0 answers
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HVAC adding C wire to older system w/ wire nuts

I have an older system, separate AC and gas heat. Trying to add a C wire. All existing wires are connected outside the air handler with wire nuts. I've unwrapped an unused blue in the lower right of ...
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0 votes
0 answers
46 views

Can I blow insulation over exposed flex ducts?

I hired some HVAC professionals to place new flex ducts above the kitchen after a soffit removal. I know putting conditioned ducts in the attic is terrible, but the ceilings were 7' and it felt like I ...
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0 votes
3 answers
60 views

Would a smart thermostat be effective for a floor with the thermostat always off?

I installed a smart thermostat on my 2nd floor since I ended up tweaking it often to reduce my electricity bill. I left the 1st floor as a dumb thermostat since I've always left it off. My upstairs ...
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  • 153
0 votes
1 answer
41 views

Can flex tape be used to repair an HVAC condensate drain pan?

I have an attic unit that was recently getting a lot of water in the pan under the full unit. The plastic condensate drain pan has a crack in it. The HVAC tech said it will cost $800 to replace the ...
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  • 153
1 vote
1 answer
56 views

How to measure current draw of AC condenser fan motor, single phase?

This question is a follow-up from a related question about an AC tech recommending a likely unnecessary fan motor replacement. See Rust on outdoor ac fan motor? Tech recommends replacement? I'm trying ...
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0 votes
0 answers
33 views

From Honeywell to Google Nest... not cooling?

I recently changed my thermostat from an old Honeywell 7-day to a Google Nest. I'm an idiot cause I didn't take a photo before replacing it. now, I feel the air is not cool, just air/fan. The NEst is ...
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0 votes
0 answers
20 views

Question about duct work replacing a bathroom fan

I am replacing a bathroom exhaust fan with a humidity sensing model that automatically turns on when a specified humidity level is reached. The original duct is 3" wide. I had to get a 4" to ...
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-4 votes
1 answer
53 views

If you tilt a air-conditioner will it keep it from coming on [closed]

Ac want come on at all is it the way it was transported
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0 votes
0 answers
32 views

Choosing Where to Place Forced Air Wall Heaters

I have a small home ~800 sq ft in a mountain climate that gets quite cold in the winters (10s-20s F in the day in the winter). I already have a pellet stove but the other existing heat comes from two ...
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3 votes
1 answer
143 views

Rust on outdoor ac fan motor? Tech recommends replacement?

I had my annual ac inspection. House has two units and one runs about twice as long each day as the other because it cools much more of the house, and had its capacitor fail two years ago. Tech ...
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3 votes
1 answer
200 views

Wiring single-phase A/C to a 240V 'wild leg'?

I'm looking to install a ductless mini-split system to cool some computer equipment in a building where the main A/C is turned off when unoccupied. It's a 9000 BTU heat pump, electrically rated at 9 ...
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  • 177
1 vote
1 answer
69 views

Should the door be open or closed between two separate HVAC systems?

We recently built out an additional 600sqft theater room in our attic. It’s a big room with 14’ high vaulted ceiling. We live in Houston and room heat load is fairly high. We installed a 2-ton unit ...
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0 votes
1 answer
61 views

Whole House Fan Emergency Shutoff / Limit Control

We are installing a whole house fan (which we already have) and would like the extra precaution of an emergency shutoff so it won’t cause extra risk of fire spread if a fire occurs (due to it causing ...
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  • 133
0 votes
2 answers
70 views

A/C Evaporator Coil - Water dripping from unknown fitting

I noticed some water dripping from my A/C's secondary condensate drain. The primary condensate drain line still has what seems like a normal flow of water coming from it, so I don't think it is ...
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  • 21
0 votes
1 answer
98 views

Found a 2"x4" hole in return duct

So this return duct in my attic has a perfectly cut 2"x4" hole in it. Why would someone have left that hole there? I live in southern Florida and the attic is usually 110-160F in the day ...
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  • 185
5 votes
2 answers
761 views

What is a Non-automatic AC Disconnect

The 10 GE AC Disconnects that comprise their list of Spec-SetterTM Safety Switches are categorized fused, no fuse and non-automatic. I want to know the definition of a non-automatic AC disconnect. GEs ...
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  • 81
-1 votes
1 answer
42 views

Does any manufacturer make a fused 240 V 60 A steel AC disconnect with GFCI receptacle? [closed]

I need a fused pullout 240 V 60A steel AC disconnect rated at 10 horse power with a built in GFCI receptacle for use as a convenience outlet required by 2020 NEC, but cannot find one available. Has ...
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  • 81
2 votes
1 answer
208 views

Why would a fusible AC disconnect require a bonded neutral when a non-fusible disconnect only requires the equipment grounding conductor?

According to the GE Spec-Setter TM datasheet their AC disconnects are comprised of three varieties: fusible, no fuse, non-automatic. A GE diagram on that datasheet for their "fusible" ...
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  • 81
0 votes
1 answer
19 views

Goodman AH2429-1A

I am trying to convert my old thermostat to a Wyze smart one and everything was going smoothly until I tried to connect the c wire adapter. I can’t find the terminals labeled YRGW like it wants me to. ...
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0 votes
4 answers
96 views

Is there a safety issue if my window AC causes lights to dim?

I've been researching this fairly common problem. However I haven't found any solutions. When my 12,000 BTU window AC first starts, the compressor it will whine for 3-5 seconds during which the lights ...
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